TWI707779B - Stretch sheet for absorbent articles and manufacturing method thereof - Google Patents

Abstract

The present invention is a kind of absorptive properties of a plurality of elastic yarns (4) arranged in a manner of extending in one direction without crossing each other in a substantially non-stretched state and joined to an extensible sheet (2, 3) over its entire length. Stretching sheet for articles (1). Part or all of the plurality of elastic yarns (4) are connected to the indented yarns (40) with more than one indented part (40k) in the cross section orthogonal to the longitudinal direction (Y). It is preferable that the shape of the cross-section orthogonal to the length direction (Y) of the inner shrinkage wire (40) has a shape in which a plurality of circles are connected in a partially repeated state, and it is preferable that the distance between the centers of adjacent circles is shorter than one of them The sum of the radius of the circle and the radius of the other circle is shorter and longer than the radius of the shorter of the radius of the one circle and the radius of the other circle.

Description

Stretch sheet for absorbent articles and manufacturing method thereof

The present invention relates to a stretch sheet for absorbent articles and a manufacturing method thereof.

As a stretch sheet, the applicant proposes a stretch sheet in which a plurality of elastic yarns arranged in a manner extending in one direction without crossing each other are joined to a stretchable sheet in a substantially non-stretched state over its entire length (see Patent Document 1).

The stretch sheet described in Patent Document 1 is manufactured through the steps of spinning a molten elastic resin from a plurality of spinning nozzles to obtain a plurality of elastic yarns in a molten or softened state. The elastic yarn is wound and extended at a specific speed, while fusing it to the sheet before curing.

In addition, regarding the manufacturing method of the stretch sheet, the applicant has proposed a method of manufacturing a stretch sheet using a spinning head having a zigzag arrangement portion in which a plurality of spinning nozzles are arranged in a so-called zigzag shape (refer to Patent Document 2). Patent Document 2 describes the use of a spinning head in which the spinning nozzles are arranged in a zigzag pattern. Specifically, a spinning head is used in which a plurality of spinning nozzles are spaced at a certain interval in one direction The arranged nozzle rows are arranged in a plurality of rows in a direction orthogonal to a direction, and among the nozzle rows adjacent in the direction orthogonal to a direction, the spinning nozzles are staggered.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2008-179128

[Patent Document 2] Japanese Patent Laid-Open No. 2017-61064

The present invention is a stretch sheet in which a plurality of elastic yarns arranged in a manner of extending in one direction without crossing each other are joined to a stretchable sheet material in a substantially non-stretched state over its entire length. In the embodiment, the stretch sheet is a stretch sheet for absorbent articles. In the embodiment, part or all of the above-mentioned elastic yarns are indented yarns having one or more indented parts in a cross section orthogonal to the extending direction of the elastic yarn.

In addition, the present invention is a method for manufacturing a shrinkable sheet. The method includes a fusion step that causes a plurality of elastic yarns in a molten or softened state ejected from a plurality of spinning nozzles to be combined with the sheet before the elastic yarn is solidified. The raw material sheet is in contact with and fused with the raw material sheet. In the embodiment, the stretch sheet is a stretch sheet for absorbent articles. In the embodiment, in the fusion step, the nozzle rows in which the plurality of spinning nozzles are arranged at intervals in the first direction are formed in a plurality of rows in the second direction orthogonal to the first direction. In the embodiment, it is used for a spinning head in which the positions of the spinning nozzles in the nozzle rows adjacent to each other in the second direction are shifted from the first direction. In the embodiment, a winding mechanism for winding the elastic yarn spun from the spinning nozzle of the above-mentioned spinning head is used. In the embodiment, the elastic yarn in the molten or softened state spun from the spinning nozzle is wound at a winding speed of 40 m/min or more and 200 m/min or less.

1: Stretch film

1': composite sheet

2: sheet

3: sheet

4: Elastic yarn

10: Spinning device

11: Spinning head

11a: Lower end

11L: bottom wall

11S: side wall

12: Spinning nozzle

12A: Serrated configuration part

12L: Nozzle row

13: Storage Department

15: nip roller

16: nip roller

17: Cogged roller

18: nip roller

40: Inner shrink wire

40k: indentation

41: Monofilament

42: Silk

43: Silk

c1: circle

c2: circle

c3: circle

c4: circle

c5: circle

D: diameter

L1: Length in the width direction

L2: Length in thickness direction

L3: Minimum length in thickness direction

L4: Length in the width direction

L5: Length in thickness direction

L6: Minimum length in thickness direction

P: Distance between ends

P1: Distance between centers

p1: pitch

P2: Distance between centers

p2: pitch

P3: Distance between centers

r1: radius

r2: radius

r3: radius

r4: radius

r5: radius

X: width direction

x1: 1st direction

Y: length direction

y1: second direction

Z: thickness direction

Figure 1 (a) is a perspective view showing the stretched state of the stretch sheet in a preferred embodiment of the present invention, and FIG. 1 (b) schematically shows the split of the stretch sheet into two sheets and a plurality of elastic threads A perspective view of the state.

Fig. 2 is a cross-sectional view schematically showing a cross-section of the stretch sheet of this embodiment (equivalent to the cross-sectional view of the A-A section of the stretch sheet shown in Fig. 1).

Fig. 3(a) schematically shows the front view of the monofilament shown in Fig. 2, and Fig. 3(b) schematically shows the front view of the inner shrinkable yarn with one inner shrinkage portion shown in Fig. 2, and Fig. 3 (c) is a schematic diagram showing the front view of the inwardly shrinkable wire having two inwardly-shaped portions shown in FIG. 2.

Fig. 4 is a perspective view schematically showing the main part of the spinning device used in the implementation of the fusion step in the manufacturing method of the stretch sheet of this embodiment.

Fig. 5 is a perspective view schematically showing the lower end surface (nozzle installation surface) side of the spinning head in the spinning device shown in Fig. 4 as the upper side.

Fig. 6 is a plan view schematically showing the lower end surface of the spinning head shown in Fig. 5.

Fig. 7 is a perspective view schematically showing the main part of the stretching device used in the implementation of the stretchability imparting step in the manufacturing method of the stretch sheet of this embodiment.

The above-mentioned stretch sheet is used for various purposes, but there may be a need to adjust the stress according to its purpose. When the stress of the stretch sheet is increased, for example, if the number of elastic threads joined to the sheet is increased, the area in the stretch sheet where there are no elastic threads becomes smaller. The above-mentioned stretch sheet is obtained by fusing the elastic filament to the sheet, so if the non-existent area of the elastic filament, that is, the elastic filament When the non-joining area becomes smaller, the thickness of the stretch sheet becomes thinner, and there is room for improvement in the touch of the skin. The elastic yarn is obtained by extending the elastic resin in a molten or softened state.

Also, for example, if the diameter of the elastic yarn is to be increased to increase the stress of the stretch sheet, the contact area between the elastic yarn and the sheet becomes larger. For example, when the sheet is processed to impart stretchability, the sheet may produce There is room for improvement in appearance such as holes.

The inventors of the present invention found that when the stress is increased, by using an elastic yarn having one or more indentations in a cross section orthogonal to the extension direction of the elastic yarn, a good touch of the skin can be obtained without reducing the surface. It is a stretch sheet that can improve the stress. In addition, the inventors of the present invention have found that by arranging the spinning nozzle in a zigzag shape and setting the winding speed of the elastic yarn in a specific speed range, the elastic yarn with the indented portion can be efficiently obtained. Moreover, in Patent Documents 1 and 2, there is no description that the stretch sheet includes such an elastic yarn having an indented portion, and that the resin spinning speed and the winding speed of the elastic yarn are set to a specific speed range.

Therefore, the present invention relates to a stretch sheet and its manufacturing method that can eliminate the problems to be solved in the prior art.

Hereinafter, the present invention will be described with reference to the drawings based on its preferred embodiments. 1 and FIG. 2 show a stretch sheet 1 of a preferred embodiment of the present invention, and FIG. 3 shows the elastic yarn 4 included in the stretch sheet 1. The stretch sheet is preferably a stretch sheet for absorbent articles.

As shown in Figures 1 and 2, the stretch sheet 1 has a structure in which a plurality of filamentous elastic threads 4 are joined to two sheets 2, 3, and the plurality of elastic threads 4 extend in one direction without crossing each other. The way to arrange. A plurality of elastic yarns 4 are respectively clamped between the two sheets 2 and 3 and are joined to the two sheets in a substantially non-stretched state over the entire length of the stretch sheet 1 in one direction (the length direction indicated by the symbol Y) 2, 3. In this specification, the so-called "elasticity" refers to the property of being stretchable and contracting when the force of self-stretching is released, and the so-called "substantially non-stretched state" refers to the state that does not contract when the external force is released.

The stretchability of the stretch sheet 1 is expressed by the elasticity of the elastic yarn 4. When the stretch sheet 1 is stretched in the same direction as the direction in which the elastic yarn 4 extends, the elastic yarn 4 and the sheets 2, 3 stretch. Moreover, when the stretch of the stretch sheet 1 is released, the elastic yarn 4 shrinks, and the sheets 2 and 3 return to the state before the stretch along with the shrinkage. In the stretch sheet 1, there are no other elastic threads that are combined in a state orthogonal to the elastic threads 4. Therefore, when the stretch sheet 1 is stretched in the same direction as the direction in which the elastic threads 4 extend, the stretch sheet 1 The so-called width shrinkage and elongation rarely occur in the direction perpendicular to the stretching direction.

Although it also depends on the specific application, the overall basis weight of the stretch sheet 1 is preferably 10 g/m ² or more, more preferably 20 g/m ² or more, and more preferably 80 g/m ² or less, more preferably 70 g/m ² or less, specifically, preferably 10 g/m ² or more and 80 g/m ² or less, more preferably 20 g/m ² or more and 70 g/m ² or less.

The thickness of the stretch sheet 1 is preferably 0.32 mm or more, more preferably 0.36 mm or more, still more preferably 0.39 mm or more, and more preferably 0.5 mm or less from the viewpoint of expressing good skin touch. It is more preferably 0.4 mm or less, specifically, 0.32 mm or more and 0.5 mm or less, more preferably 0.36 mm or more and 0.5 mm or less, and still more preferably 0.39 mm or more and 0.4 mm or less. The thickness of the stretch sheet 1 is measured in the following manner. That is, the sheet to be measured is sandwiched between the plates with a load of 0.5 cN/cm ² , and the distance between the plates is measured, whereby the thickness of the sheet to be measured can be measured.

Regarding the peeling strength of the stretch sheet 1 (the peel strength of the respective sheets 2, 3 with respect to the elastic yarn 4), it is a viewpoint to prevent the expression of openings and the like when stretchability is imparted to the composite sheet 1'in the following stretchability imparting step In particular, it is preferably 5 cN/bar or more, more preferably 10 cN/bar or more, more preferably 30 cN/bar or less, more preferably 20 cN/bar or less, and more preferably 18 cN/bar or less, specifically, It is preferably 5 cN/line or more and 30 cN/line or less, more preferably 10 cN/line or more and 20 cN/line or less, and still more preferably 10 cN/line or more and 18 cN/line. The peel strength of the stretch sheet 1 was measured as follows. That is, after clamping the two sheets 2 and 3 of the stretch sheet 1 as the measurement target sheet, respectively, the sheet 2 is peeled off at a speed of 300 mm/min. By measuring the maximum load at this time, the peel strength of the stretch sheet 1 can be measured.

Regarding the stretch sheet 1, from the viewpoint of making it exhibit sufficient stretch characteristics, the load is when it is stretched 100% along the direction in which the elastic yarn 4 extends and is restored to 50% from this state (hereinafter also referred to as 50% restoration load ) And the load when the elastic yarn 4 is extended by 50% (hereinafter also referred to as 50% progress load) (50% restoration load/50% progress load) is preferably 45% or more. It is preferably 50% or more, and more preferably 100% or less, specifically, it is preferably 45% or more and 100% or less, and more preferably 50% or more and 100% or less.

As a 50% recovery load, from the same viewpoint, it is preferably 80 cN/50mm or more, more preferably 120 cN/50mm or more, and more preferably 150 cN/50mm or less, more preferably 135 cN/50mm or less, specifically , Preferably above 80cN/50mm, 150cN/50mm Below, it is more preferably 120 cN/50mm or more and 135 cN/50mm or less.

As the 50% progress load, from the same viewpoint, it is preferably 80cN/50mm or more, more preferably 120cN/50mm or more, still more preferably 245cN/50mm or more, and more preferably 600cN/50mm or less, more preferably 300cN/50mm or less, more preferably 250cN/50mm or less, specifically, preferably 80cN/50mm or more and 600cN/50mm or less, more preferably 120cN/50mm or more and 300cN/50mm or less, and still more preferably 245cN/50mm Above 250cN/50mm or less.

(Measurement method of 50% restoration load and 50% progress load)

A tensile tester (AG-IS manufactured by Shimadzu Corporation) was used to perform a 100% elongation cycle test of the stretch sheet. Specifically, first, prepare a sample of the stretch sheet used in the 100% extension cycle test, make the extension direction of the elastic yarn stretch consistent with the stretching direction, and install the sample in a tensile testing machine. The distance between the chucks at this time is set to 150mm. The sample was extended by 150 mm in the direction of extension and contraction of the sample at a speed of 300 mm/min (the distance between the chucks became 300 mm in total), and immediately returned to the original length at a speed of 300 mm/min. Furthermore, the initial length between the chucks can be changed according to the length of the target sample.

Furthermore, in the 100% elongation cycle test, the so-called 100% elongation refers to the state where the sample is stretched to twice the initial length. Also, in the process of elongating to 100% elongation, the elongation at the point when the elongation becomes 50%, that is, the point when it becomes 1.5 times the initial length, is set as the "50% progressive load", and the elongation reaches the elongation. In the process of recovering to the initial length after the rate of 100%, the tensile force at the point when the elongation becomes 50% is set to "50% recovery load".

In addition, when measuring the condition of a stretch sheet assembled in an absorbent article such as a commercially available diaper, the adhesive used for the absorbent article is dissolved with an organic solvent, and the stretch sheet is taken out. Use it at this time Organic solvents will not dissolve elastomers. Then, after drying the taken-out stretch sheet, the stretch sheet is measured by the above-mentioned measuring method. Regarding other measurements described in this manual, it is also provided for each measurement after drying the stretch sheet taken out as described above.

Both sheets 2 and 3 constituting the stretch sheet 1 can be stretched. The two sheets 2 and 3 are made of fibers that are substantially inelastic, typically those made of inelastic fibers, are substantially inelastic, and are typically inelastic. Each of the sheets 2 and 3 can be stretched in the same direction as the direction in which the elastic yarn 4 extends (the longitudinal direction indicated by the symbol Y in FIG. 1). In this specification, the so-called "stretchable" includes the following situations: (A) the constituent fibers of the sheets 2 and 3 are stretched; (B) even if the constituent fibers themselves are not stretched, the fibers bonded at the intersection are separated from each other, or by The three-dimensional structure formed by a plurality of fibers due to the combination of fibers changes the structure, or the constituent fibers are broken, or the slack of the fibers is stretched, so that the entire non-woven fabric is stretched.

The plurality of elastic yarns 4 constituting the stretch sheet 1 are substantially continuous over the entire length of the stretch sheet 1, and are typically continuous throughout the entire length as in the embodiment shown in FIG. 1. Each elastic yarn 4 contains elastic resin. The plurality of elastic yarns 4 are arranged in a manner of extending in one direction without crossing each other in a direction orthogonal to the extending direction. As long as the elastic yarns 4 do not cross each other, they may extend linearly, or they may extend while meandering. In addition, the extending direction, which is the direction in which the elastic yarn extends, typically coincides with the longitudinal direction Y, and the direction orthogonal to the extending direction typically coincides with the width direction X.

Each elastic yarn 4 is joined to the sheets 2 and 3 in a substantially non-stretched state. Since the elastic yarn 4 is joined to the sheets 2 and 3 in an unstretched state, the stretch sheet 1 does not produce slack (creeping) due to elongation. Change), and has the advantage of not being easily reduced. In addition, there is an advantage that it can be stretched to the length that the sheets 2 and 3 can stretch or the maximum elongation rate of the elastic yarn 4. Preferably, each elastic yarn 4 is fused to the stretchable sheets 2 and 3 over its entire length in a substantially non-stretched state. Here, the term "fusion" does not mean that the elastic yarn 4 is joined to the sheets 2 and 3 via a third component such as an adhesive, but refers to at least the resin constituting the elastic yarn 4 and the resin constituting the sheets 2, 3 One melts and joins the two.

Regarding the distance P between the ends of the elastic yarns 4 adjacent to each other in the width direction X (refer to FIG. 2), from the viewpoint of expressing a good skin touch, it is preferably 0.4 mm or more, more preferably 0.6 mm or more, In addition, it is preferably 1.2 mm or less, more preferably 1 mm or less, still more preferably 0.8 mm or less, more preferably 0.4 mm or more and 1.2 mm or less, more preferably 0.6 mm or more and 1 mm or less, and still more preferably 0.6 mm Above 0.8mm. The distance P between the ends can be fixed between all the elastic yarns, and can also be different between one elastic yarn and other elastic yarns as shown in FIG. 2. When the distance P between the ends is not fixed, it is preferable that the average value of the distance between the ends of the elastic yarns is within the above-mentioned preferable range, and it is more preferable that the distance between the ends of all the elastic yarns is the above-mentioned preferable range Within range.

(Method for measuring the distance between the ends of adjacent elastic yarns)

The distance P between the ends of adjacent elastic yarns 4 is measured by magnifying the cut surface obtained by cutting the sample of the stretch sheet in the width direction with a microscope. The measurement is carried out at 100 arbitrary locations, and the average value is the average value of the distance between the ends. In addition, the measurement is to cut out a plurality of cut surfaces with different positions in the longitudinal direction, and measure the distance between the ends of adjacent elastic yarns in the plurality of cut surfaces.

Among the elastic yarns 4 included in the stretch sheet 1, a part of the elastic yarns has at least one indentation in a cross section (hereinafter also referred to as a cross section in the width direction) orthogonal to the extending direction (length direction Y) of the elastic yarn. The constricted yarn 40 of the portion 40k, as the elastic yarn 4, includes a monofilament 41 that does not have the constricted portion 40k, and the constricted yarn 40 having one or more such constricted portions 40k. Here, the so-called thread having one indentation in the cross section orthogonal to the extending direction means that when the cross section orthogonal to the extending direction of the thread is observed, there is a pair of depressions from the peripheral surface of the thread toward the inner side of the cross section The location. For example, the so-called having two indented parts means that there are two pairs of the concave parts. More specifically, in the embodiment shown in FIG. 2, the indented yarn 40 includes a yarn 42 having one indented portion 40k and a yarn 43 having two indented portions 40k. Furthermore, all the elastic yarns 4 contained in the stretch sheet for absorbent articles of the present invention may be inward yarns 40 having one or more indented portions.

The monofilament 41 is obtained by extending the molten resin ejected from the spinning nozzle 12 described below on a spinning line. As shown in FIG. 3(a), the diameter D of the monofilament 41 is not particularly limited, but from the viewpoint of the balance between the texture of the stretch sheet 1 and the productivity of the elastic yarn 4, it is preferably 40 μm or more, and more It is preferably 80 μm or more, more preferably 200 μm or less, more preferably 180 μm or less, furthermore, 40 μm or more and 200 μm or less, and more preferably 80 μm or more and 180 μm or less. The diameter of the monofilament 41 is determined by the diameter of the spinning nozzle 12 described below.

The inner shrinkage yarn 40 is obtained by bonding two or more monofilaments ejected from two or more adjacent spinning nozzles 12 to each other in the middle of stretching. The shape of the cross-section in the width direction of the inner shrinkage yarn 40 has a shape in which a plurality of circles are partially repeated and connected in the width direction X. Specifically, the shape of the cross-section in the width direction of the thread 42 with one indented portion is shown in Fig. 3(b). The two circles c1 and c2 are partially overlapped and connected in the width direction X. 2 retracted parts of silk 43 The shape of the cross-section in the width direction is shown in Fig. 3(c), where three circles c3, c4, and c5 are partially overlapping and connected in the width direction X. The part where a part of the connected circle is repeated is the part surrounded by a dashed arc in the connecting part of the adjacent circle and the circle in Fig. 3(b) and Fig. 3(c).

In this way, by setting the shape of the cross section in the width direction to a shape in which a plurality of circles are partially repeated, that is, providing one or more indentations 40k in the cross section in the width direction, for example, and increasing the number of monofilaments 41 In different situations, it is possible to increase the stress of the elastic sheet 1 while suppressing the distance between the ends of adjacent elastic yarns 4 from decreasing. That is, by keeping the thickness of the stretch sheet 1 thick, it is possible to improve the stress of the stretch sheet 1 while making the skin feel good. In addition, compared with the case where the diameter of the monofilament 41 is increased and the cross-sectional area is increased, the increase in the contact area between the sheets 2, 3 and the elastic yarn 4 can be suppressed. That is, while increasing the cross-sectional area of the elastic yarn 4 and increasing the stress of the stretch sheet 1, it is possible to suppress openings and the like in the following stretchability imparting step to maintain a good appearance. In this way, according to the stretch sheet of the present embodiment, the skin feels good, and while maintaining a good appearance, the stress of the elastic yarn 4 can be increased.

The indented portion 40k of the indented yarn 40 extends along the extending direction (lengthwise direction Y) of the elastic yarn 4 as shown in FIG. 1(b). The stretch sheet 1 has an inward shrinkage portion 40k extending along the extending direction of the elastic thread 4 by the inward shrinkage thread 40, which can make the skin feel good and maintain a good appearance while further increasing the stress of the elastic thread 4.

Regarding the shrinkage yarn 40, from the viewpoint of expressing a good skin touch and maintaining a good appearance, it is preferable that the distance between the centers of adjacent circles P1 is larger than the radius of one circle and another The sum of the radii of one circle is smaller than the radius of one circle and the other The shorter of the radii of the circle has the longer radius. Specifically, as shown in Fig. 3(b), in the wire 42 with one indentation, it is preferable to have a cross-sectional shape in the width direction. The distance P1 between the centers of adjacent circles c1 and c2 is longer The sum of the radius r1 of one circle c1 and the radius r2 of the other circle c2 (r1+r2) is smaller, and is smaller than the radius of the shorter one of the radius r1 of one circle c1 and the radius r2 of the other circle c2 (for example The radius r1) of one of the circles c1 is longer. The radius r1 of the circle c1 and the radius r2 of the circle c2 are preferably radii along the width direction X.

Similarly, as shown in Fig. 3(c), the wire 43 with two indentations is preferably in the cross section in the width direction. The distance P2 between the centers of adjacent circles c3 and c4 is larger than the radius r3 of one of the circles c3. The sum of the radius r4 with the other circle c4 (r3+r4) is smaller, and is smaller than the radius r3 of one circle c3 and the radius r4 of the other circle c4 (for example, the radius of one circle c3) r3) Longer. Moreover, it is preferable that the distance P3 between the centers of adjacent circles c4 and c5 is smaller than the sum (r4+r5) of the radius r4 of one of the circles c4 and the radius r5 of the other circle c5, and is smaller than that of the one of the circles c4 The radius of the shorter one of the radius r4 and the radius r5 of the other circle c5 (for example, the radius r4 of one of the circles c4) is longer. The radius r3 of the circle c3 and the radius r5 of the circle c5 are preferably the radius along the width direction, and the radius r4 of the circle c4 is preferably the radius along the thickness direction Z.

In the cross section in the width direction of the inward filament 40 (the cross section orthogonal to the extending direction), the maximum length in the width direction X of the inward filament is preferably 100 μm or more, more preferably 200 μm or more, and more preferably 800 μm or less , More preferably 400 μm or less, still more preferably 500 μm or less, particularly preferably 270 μm or less, specifically, preferably 100 μm or more and 800 μm or less, more preferably 100 μm or more and 400 μm or less, and more preferably 200 μm or more and 500 μm or less. It is preferably 200 μm or less and 270 μm or less. The maximum length in the width direction X of the above-mentioned inner shrinkage yarn is the maximum length in the width direction cross section of the inner shrinkage yarn, which is measured by the following method.

(Measuring method of the maximum length in the width direction of the shrinkage yarn)

The maximum length in the width direction X of the inner shrinkage yarn 40 is measured by magnifying the cut surface when the sample of the stretch sheet is cut in the width direction with a microscope. The measurement is performed on any 30 locations where the position of one inner shrinkage yarn in the longitudinal direction is different, and the average value is set as the maximum length of the inner shrinkage yarn 40 in the width direction.

Regarding the silk 42 with one indentation, from the viewpoint of making it express a good skin touch, as shown in Figure 3(b), the ratio of the length L2 in the thickness direction Z to the length L1 in the width direction X ((L2/L1)×100) is preferably 10% or more, more preferably 30% or more, more preferably 60% or less, more preferably 50% or less, specifically, preferably 10% or more 60 % Or less, more preferably 30% or more and 50% or less. Furthermore, the length L1 in the width direction X of the thread 42 with one indentation refers to the maximum length in the width direction X, and the length L2 in the thickness direction Z of the thread 42 with one indentation refers to the thickness direction Z The maximum length of the upper part is the diameter.

From the same point of view, the ratio of the minimum length L3 in the thickness direction Z of the indented portion 40k to the length L2 in the thickness direction Z ((L3/L2)×100) of the thread 42 with one indentation is preferably 5% or more, more preferably 10% or more, more preferably 50% or less, more preferably 30% or less, specifically, preferably 5% or more and 50% or less, more preferably 10% or more and 30% or less .

From the same point of view, the length L1 in the width direction X of the thread 42 with one inwardly-shaped portion is preferably 100 μm or more, more preferably 200 μm or more, and more preferably 400 μm or less, more preferably 300 μm or less. In particular, it is preferably from 100 μm to 400 μm, and more preferably from 200 μm to 300 μm.

From the same point of view, the length L2 in the thickness direction Z of the inner shrinkage yarn 40 is preferably 80 μm or less Above, it is more preferably 100 μm or more, and more preferably 200 μm or less, more preferably 180 μm or less, specifically, preferably 80 μm or more and 200 μm or less, and more preferably 100 μm or more and 180 μm or less.

From the same point of view, the minimum length L3 in the thickness direction Z of the inner shrinkage portion 40k of the inner shrinkage yarn 40 is preferably 5 μm or more, more preferably 10 μm or more, and more preferably 60 μm or less, more preferably 50 μm or less Specifically, it is preferably 5 μm or more and 60 μm or less, and more preferably 10 μm or more and 50 μm or less.

Regarding the silk 43 with two indentations, from the viewpoint of making it express a good skin touch, as shown in Fig. 3(c), the ratio of the length L5 in the thickness direction Z to the length L4 in the width direction X ((L5/L4)×100) is preferably 5% or more, more preferably 10% or more, more preferably 60% or less, more preferably 50% or less, specifically, preferably 5% or more 60 % Or less, more preferably 10% or more and 50% or less. Furthermore, the length L4 in the width direction X of the thread 43 with two indentations refers to the maximum length in the width direction X, and the length L5 in the thickness direction Z of the thread 43 with two indentations refers to the thickness direction Z The maximum length above.

For the yarn 43 with two indentations, from the same point of view, the ratio of the minimum length L6 in the thickness direction Z at the indentation part 40k to the length L5 in the thickness direction Z ((L6/L5)×100) is preferable 5% or more, more preferably 10% or more, more preferably 50% or less, more preferably 30% or less, specifically, preferably 5% or more and 50% or less, more preferably 10% or more and 30% the following.

From the same point of view, the length L4 of the width direction X of the thread 43 having two indentations is preferably 200 μm or more, more preferably 300 μm or more, and more preferably 600 μm or less, more preferably 500 μm or less. In general, it is preferably 200 μm or more and 600 μm or less, more preferably 300 Above μm and below 500 μm.

From the same point of view, the length L5 of the thickness direction Z of the thread 43 having two indentations is preferably 80 μm or more, more preferably 100 μm or more, and more preferably 200 μm or less, more preferably 180 μm or less. In particular, it is preferably 80 μm or more and 200 μm or less, and more preferably 100 μm or more and 180 μm or less.

From the same point of view, the minimum length L6 in the thickness direction Z at the indented portion 40k of the thread 43 having two indented portions is preferably 5 μm or more, more preferably 10 μm or more, and more preferably 60 μm or less, It is more preferably 50 μm or less, specifically, preferably 5 μm or more and 60 μm or less, and more preferably 10 μm or more and 50 μm or less.

In the stretch sheet 1, the ratio of the number of shrinkable filaments 40 to the number of elastic filaments 4 ((number of shrinkable filaments 40/ The number of elastic yarns 4)×100) is preferably 5% or more, more preferably 20% or more, still more preferably 50% or more, and more preferably 90% or less, more preferably 80% or less, and more It is preferably 70% or less, specifically, 5% or more and 90% or less, more preferably 20% or more and 80% or less, and still more preferably 50% or more and 70% or less. In addition, the shrinkage yarn 40 in the embodiment shown in Fig. 2 etc. is formed by a plurality of yarns immediately after spinning, but as the "number of elastic yarns", it is directly incorporated in the state immediately after spinning. The yarn of the stretch sheet 1, the yarn 42 with one inward part, and the yarn 43 with two inward parts are counted as "1" respectively.

In the case where the plurality of elastic yarns 4 include a plurality of inner shrinkage yarns 40, the ratio of the number of yarns 42 with 1 shrinkage portion to the number of inner shrinkage yarns 40 ((a yarn with 1 shrinkage portion The number of strands of 42/the number of strands of inner shrinkage wire 40)×100) From the same point of view, it is preferably 50% or more, more preferably 60% Above, more preferably 90% or more, and more preferably 100% or less, specifically, 50% or more and 100% or less, more preferably 60% or more and 100% or less, and still more preferably 90% or more Below 100%.

Next, if the material for forming the stretch sheet 1 is described, as the sheets 2 and 3, for example, non-woven fabrics such as hot-air non-woven fabrics, hot-rolled non-woven fabrics, spunlace non-woven fabrics, spunbonded non-woven fabrics, and meltblown non-woven fabrics can be used. The non-woven fabrics can be non-woven fabrics of continuous filaments or short fibers. The sheets 2 and 3 may be of the same type or different types. The "same type of sheets" herein refers to sheets whose manufacturing process, types of constituent fibers of the sheet, fiber diameter or length of the constituent fibers, thickness or basis weight of the sheet are the same. When at least one of them is different, it is a "different type of sheet".

The thickness of the sheets 2 and 3 is preferably 0.05 mm or more, more preferably 0.1 mm or more, still more preferably 0.15 mm or more, preferably 5 mm or less, more preferably 1 mm or less, and further preferably 0.5 mm or less. In particular, it is preferably 0.05 mm or more and 5 mm or less, more preferably 0.1 mm or more and 1 mm or less, and still more preferably 0.15 mm or more and 0.5 mm or less. The thickness can be measured with a load of 0.5cN/cm ² sandwiched between the plates, and the cross-section of the stretch sheet 1 can be observed with a microscope at a magnification of 50 to 200 times, and the average thickness can be calculated under each field of view, and taken as the thickness of the 3 fields Find the average value. The overall thickness of the sheet is obtained by measuring the distance between the plates. Regarding the basis weight of the sheets 2 and 3, from the viewpoints of texture, thickness, and design, each is preferably 3 g/m ² or more, more preferably 5 g/m ² or more, and more preferably 100 g/m ² Hereinafter, it is more preferably 30 g/m ² or less, specifically, 3 g/m ² or more and 100 g/m ² or less, and more preferably 5 g/m ² or more and 30 g/m ² or less.

As the constituent fibers of the sheets 2, 3, for example, a substantially inelastic inelastic fiber can be used In this case, the sheets 2 and 3 can become extensible fiber layers mainly composed of the inelastic fibers. Examples of the inelastic fibers include polyesters and polyamides such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or polybutylene terephthalate (PBT). Amine and other fibers. The constituent fibers of the sheets 2 and 3 may be short fibers or long fibers, and may be hydrophilic or water-repellent. In addition, core-sheath type or side-by-side type composite fibers, split fibers, profiled fibers, crimped fibers, heat-shrinkable fibers, etc. may also be used. These fibers can be used individually by 1 type or in combination of 2 or more types.

A preferable example of the constituent fibers of the sheets 2 and 3 includes two or more components including a low melting point component and a high melting point component. In this case, at least the constituent fibers of the low-melting component are joined at the fiber intersections by heat fusion. As a core-sheath type composite fiber containing two or more components of a low-melting component and a high-melting component, it is preferable that the core is high-melting-point PET, PP and sheath-based low-melting-point PET, PP, PE. In particular, if these composite fibers are used, the fusion with the elastic yarn 4 becomes stronger, and peeling between the two becomes less likely to occur, which is preferable.

The elastic yarn 4 is one made of, for example, an elastic resin such as a thermoplastic elastomer or rubber as a raw material. In particular, if a thermoplastic elastomer is used as a raw material, it can be melt-spinning using an extruder in the same way as a normal thermoplastic resin, and the elastic yarn obtained in this way is easy to heat fusion, so it is suitable for stretch sheets 1. As thermoplastic elastomers, for example, SBS (styrene-butadiene-styrene), SIS (styrene-isoprene-styrene), SEBS (styrene-ethylene-butadiene-styrene), SEPS (styrene-ethylene-propylene-styrene) and other styrene-based elastomers, olefin-based elastomers (ethylene-based α-olefin elastomers, propylene-based elastomers obtained by copolymerizing ethylene, butene, and octene) , Polyester elastomer, polyurethane elastomer, etc., one of them can be used alone or Combine 2 or more types.

Next, taking the manufacturing method of the stretch sheet 1 of the aforementioned embodiment as an example, the manufacturing method of the stretch sheet 1 of the present invention will be described with reference to FIGS. 4 to 7. The spinning device 10 and the stretching device used in the manufacturing method of a preferred embodiment of the stretch sheet 1 are shown in FIGS. 4-7.

As shown in FIG. 4, the spinning device 10 is provided with: a spinning head 11 that spins molten resin from a spinning nozzle to form an elastic yarn 4 in a molten or softened state; and a pair of nip rollers 15, 15, etc. It serves as a winding mechanism for winding a plurality of elastic yarns 4 ejected from the spinning head 11. The pair of nip rollers 15, 15 are typically smooth rollers. The spinning device 10 is a device for spinning by the so-called melt blowing method. In addition to the spinning head 11, the spinning device 10 is also equipped with a melt extruder (not shown) that melts and sends out the elastic resin chips to the spinning head 11 The basic structure is the same as that of the spinning device of the known meltblown method. In addition, the spinning head 11 and the pair of nip rollers 15, 15 are electrically connected to a control part not shown, and the resin ejection speed of the spinning head 11 and the roll of the pair of nip rollers 15, 15 can be adjusted by the control part. Take the speed.

As shown in FIG. 5, the spinning head 11 includes a bottom wall portion 11L of a rectangular shape in plan view that forms the lower end surface 11a of the head 11, and a side wall portion 11S connected to the periphery of the bottom wall portion 11L, and is composed of The inner space of the spinning head 11 divided by the wall portions 11L and 11S becomes the storage portion 13 of the molten resin supplied from the above-mentioned melt extruder. A plurality of spinning nozzles 12 are penetrated on the lower end surface 11 a of the spinning head 11, and the storage portion 13 of the spinning head 11 communicates with the outside through each spinning nozzle 12. The material of the spinning head 11 can be set in the same manner as a known one, and it is usually metal.

As shown in Figures 5 and 6, the nozzle setting surface of the spinning head 11, that is, the lower end surface 11a, is provided with a saw The zigzag arrangement part 12A of a plurality of spinning nozzles 12 is arranged in a tooth shape. In the zigzag arrangement portion 12A, the nozzle row 12L (the part enclosed by the dotted line in FIG. 6) of the plurality of spinning nozzles 12 is arranged at intervals in the first direction x1 of the lower end surface 11a in the first direction x1 The orthogonal second direction y1, that is, the width direction of the lower end surface 11a forms a plurality of rows (two rows in this embodiment), and in the first direction x1, the nozzles are spinning in the adjacent nozzle rows 12L and 12L. The positions of 12 are staggered by half a pitch. In this specification, "arrangement in a zigzag pattern" includes not only the state where the plural spinning nozzles 12 are perfectly arranged as described above, but also the state where the inevitable deviations in manufacturing and other minor deviations are not intentionally arranged. kind.

The spinning nozzle 12 in the spinning head 11 has a circular shape in plan view. However, in the present invention, the shape of the spinning nozzle in plan view is not particularly limited, and can be any shape such as a polygonal shape. The diameter of the circular spinning nozzle 12 in the top view will affect the diameter of the elastic yarn 4 and the stretching ratio. From this viewpoint, the diameter of the spinning nozzle 12 is preferably 0.1 mm or more, more preferably 0.2 mm or more, more preferably 2 mm or less, more preferably 0.6 mm or less, and specifically, preferably 0.1 mm Above 2mm, more preferably 0.2mm or more and 0.6mm or less.

When the diameter of the spinning nozzle 12 is within the above range, in the nozzle row 12L in the zigzag arrangement portion 12A, the distance between the centers of adjacent spinning nozzles 12 and 12 in the first direction x1 (pitch p1 ) From the viewpoint of stress performance, it is preferably 0.5 mm or more, more preferably 0.8 mm or more, more preferably 2 mm or less, more preferably 1.5 mm or less, and specifically, preferably 0.5 mm or more and 2 mm or less , More preferably 0.8mm or more and 1.5mm or less. In each nozzle row 12L, all the spinning nozzles 12 are arranged at equal intervals.

When the diameter of the spinning nozzle 12 is within the above range, in the nozzle rows 12L and 12L adjacent in the second direction y1, any one of the spinning nozzles 12 in one of the nozzle rows 12L (hereinafter referred to as specific The distance between the nozzle 12) and the center of the spinning nozzle 12 closest to the specific nozzle 12 in the first direction x1 in the other nozzle row 12L (pitch p2) From the viewpoint of skin touch, it is preferably 0.3 mm or more , More preferably 0.5 mm or more, more preferably 1 mm or less, more preferably 0.8 mm or less, specifically, preferably 0.3 mm or more and 1 mm or less, more preferably 0.5 mm or more and 0.8 mm or less.

The manufacturing method of the stretch sheet 1 of the present embodiment includes a fusion step and a stretchability imparting step. The fusion step is as shown in FIG. 4, while multiple spinning or softening states are ejected from a plurality of spinning nozzles 12 The elastic yarn 4 is wound and stretched, and the elastic yarn 4 is fused to the raw material sheets 2', 3'of the sheets 2, 3 before the elastic yarn 4 is solidified. The stretchability imparting step is as shown in Figure 7. The composite sheet 1'obtained by the fusion step is subjected to stretching processing.

First, by a melt extruder (not shown) connected to the spinning head 11, the elastic resin fragments used as the raw material of the elastic yarn 4 are melted and kneaded, and the molten elastic resin is supplied to the spinning head 11 for storage Section 13 (refer to Figure 5). The thus supplied elastic resin in the molten state is ejected from the plurality of spinning nozzles 12 provided on the lower end surface of the spinning head 11 as the elastic yarn 4 in the molten or softened state as shown in FIG. 4 at the resin ejection speed V1. As mentioned above, the plurality of spinning nozzles 12 are arranged in a zigzag shape. Therefore, the plurality of elastic yarns 4 spun from each spinning nozzle 12 do not cross each other and maintain the shape of a single elastic yarn 4 after extending to reach the sheet During the period from the confluence position of the raw material sheets 2'and 3'of the materials 2, 3, a part of the adjacent single elastic yarns 4 are bonded to each other. Adjacent single elastic yarns 4 are cooled to a certain extent on the upstream side and adhered to the downstream side while being cooled. Knot.

As shown in Fig. 4, the ejected plural elastic yarns 4 in the molten or softened state are respectively merged with the raw material sheets 2', 3'wound from the original sheet at the same speed, and are clamped between the two raw material sheets 2', 3 In the middle, it is wound up by a pair of nip rollers 15, 15 at a winding speed V2.

The resin ejection speed V1 and the winding speed V2 of the elastic yarn 4 not only affect the diameter and elongation ratio of the elastic yarn 4, but also affect the adhesiveness of the adjacent single elastic yarn 4. In order to efficiently manufacture the shrinkable yarn 40 shown in FIGS. 2 and 3, it goes without saying that the spinning head 11 is used, but it is also effective to adjust the resin ejection speed V1 and the winding speed V2 of the elastic yarn 4. When the plural spinning nozzles 12 of the spinning head 11 are linearly arranged in a row as before, there are adjacent single elastic yarns 4 on the upstream side of each other, that is, the higher one just after the spinning nozzles are ejected In the case of a large diameter due to adhesion in the molten state, the area of adhesion to the raw material sheets 2', 3'becomes larger, and there is room for improvement such as openings. In addition, if only the spinning head 11 in which the spinning nozzle 12 is arranged in a zigzag shape is used, the shape of a single elastic yarn 4 is maintained and the inner shrinkage yarn 40 is not formed in many cases. However, by using a spinning head 11 in which a plurality of spinning nozzles 12 are arranged in a zigzag shape as in this embodiment, the winding speed V2, especially the resin ejection speed V1 and the winding speed V2 are adjusted to the following speeds , Can efficiently manufacture the shrinkable wire 40.

Regarding the ratio of the winding speed V2 of the pair of nip rollers 15, 15 to the resin ejection speed V1 of the spinning head 11 ((V2/V1)×100), from the viewpoint of efficiently producing the inner shrinkage yarn 40, It is preferably 500% or more, more preferably 1000% or more, and more preferably 2500% or less, and more preferably 2000% or less.

Regarding the resin ejection speed V1 of the spinning head 11, from the same viewpoint, it is preferably 5m/min or more, more preferably 8m/min or more, and more preferably 30m/min or less, more preferably 25m/min Hereinafter, specifically, it is preferably 5 m/min or more and 30 m/min or less, and more preferably 8 m/min or more and 25 m/min or less.

Regarding the winding speed V2 of the pair of nip rollers 15, 15 from the same viewpoint, it is preferably 40m/min or more, more preferably 70m/min or more, and more preferably 200m/min or less, more preferably 180 m/min or less, specifically, it is preferably 40 m/min or more and 200 m/min or less, and more preferably 70 m/min or more and 180 m/min or less.

In particular, in order to efficiently manufacture the thread 42 with one indentation, the winding speed V2 of the pair of nip rollers 15, 15 is preferably 50m/min or more, more preferably 70m/min or more, and more preferably It is 180 m/min or less, more preferably 150 m/min or less, specifically, it is preferably 50 m/min or more and 180 m/min or less, and more preferably 70 m/min or more and 150 m/min or less.

The elastic yarn 4 in the molten or softened state merges with the raw material sheets 2', 3'in a fusionable state before it is solidified. As a result, the elastic yarn 4 is fused to the raw material sheets 2', 3'while being sandwiched by the raw material sheets 2', 3'. That is, by fusing the elastic yarn 4 before curing to the conveyed raw material sheet 2', 3', the elastic yarn 4 is wound up and stretched. When the elastic yarn 4 is fused, no heat is applied to the raw material sheets 2', 3'from the outside. That is, the elastic yarn 4 and the two raw material sheets 2', 3'are fused only by the fusion heat generated by the fuseable elastic yarn 4. As a result, among the constituent fibers of the two raw material sheets 2'and 3', only the fibers existing around the elastic yarn 4 are fused with the elastic yarn 4, and the fibers existing farther away are not fused. As a result, the heat applied to the two raw material sheets 2', 3'is controlled to a minimum. Therefore, if the two raw material sheets 2', 3'are, for example, non-woven fabrics, the original good texture of the non-woven fabric itself can be maintained. Thereby, the texture of the obtained stretch sheet 1 becomes good.

Before the spun elastic yarn 4 in the molten or softened state merges with the raw material sheets 2', 3', the elastic yarn 4 extends and the molecules are aligned in the extending direction. Also, the diameter becomes smaller. From the viewpoint of fully extending the elastic yarn 4 and the viewpoint of preventing the breakage of the elastic yarn 4, the spun elastic yarn 4 can also be blown with air of a specific temperature (hot air, cold air) to adjust the elastic yarn 4 temperature. In addition, the extension of the elastic yarn 4 is not only the extension of the resin composition (elastic resin) constituting the elastic yarn 4 in the molten state (melt extension), but also the extension (softening extension) of the softened state during the cooling process.

In order to perform fiber fusion reliably, the temperature of the elastic yarn 4 when the elastic yarn 4 is merged with the raw material sheets 2', 3'is preferably 100°C or higher, more preferably 120°C or higher. In addition, from the viewpoint of maintaining the shape of the elastic yarn 4 and obtaining a stretch sheet 1 with good stretch characteristics, the temperature of the elastic yarn 4 at the time of merging is preferably 180° C. or less, more preferably 160° C. or less. The temperature of the elastic yarn 4 at the time of this merging is specifically preferably 100°C or more and 180°C or less, more preferably 120°C or more and 160°C or less. The temperature at the time of this merging, that is, when the elastic yarn 4 and the raw material sheets 2', 3'are joined, can be measured by the following method: using a modified polyethylene or a modified polyethylene having a melting point different from that of the resin composition constituting the elastic yarn 4 A film of modified polypropylene or the like was used as a laminate base material bonded to the elastic yarn 4, and the bonding state was observed. At this time, if the elastic yarn 4 is fused with the laminated base material, the bonding temperature is higher than the melting point of the laminated base material.

When the elastic yarn 4 merges with the raw material sheets 2', 3'(at the time of joining), the elastic yarn 4 is in a substantially non-stretched state (a state that does not shrink when the external force is released). In the joined state of the two, at least a part of the constituent fibers of the raw material sheet 2', 3'is fused to the elastic yarn 4, or, more preferably, at least a part of the constituent fiber of the elastic yarn 4 and the raw material sheet 2', 3' The two are fused. The reason is that sufficient bonding strength can be obtained. The stretch characteristics of the obtained stretch sheet 1 are affected by the elastic yarn 4 and the raw sheet 2', 3' The density of the junction point. In addition, the expansion and contraction characteristics can be adjusted not only by the bonding temperature and the bonding pressure, but also by the stretching of the raw material sheets 2'and 3'(see FIG. 7) by the following elastic expression processing. By fusing the constituent fibers of the raw material sheets 2', 3'to the elastic yarn 4, the joining strength of each joining point becomes higher. If the density of the joint is lowered, the expansion and contraction resistance of the raw sheets 2', 3'will be reduced, and the stretch sheet 1 having sufficient joint strength can be obtained, which is preferable.

When the plurality of elastic yarns 4 are merged with the raw material sheets 2'and 3', the elastic yarns 4 (monofilament 41 and each shrinkable yarn 40) are arranged in one direction without crossing each other. Then, in a state where the elastic yarn 4 is merged with the raw material sheets 2', 3'and the elastic yarn 4 is sandwiched between the two raw material sheets 2', 3', the pair of nip rollers 15, 15 clamp the Three of them. The clamping conditions will affect the texture of the obtained stretch sheet 1. If the clamping pressure is large, the elastic yarn 4 is likely to sink into the two raw material sheets 2', 3'. Therefore, from the viewpoint of texture, the pinching force of the pair of nip rollers 15 and 15 only needs to be the extent to which the elastic yarn 4 contacts the two raw material sheets 2', 3', and excessive pinching force is not required. Through the above fusion step, a composite sheet 1'with elastic filaments 4 sandwiched and fixed between two raw material sheets 2'and 3'is obtained.

FIG. 7 shows the implementation of one aspect of the scalability imparting step (flexibility performance processing). The stretchability imparting step is the following step, that is, after the elastic yarn 4 is fused to the raw material sheet 2', 3', the raw material sheet 2', 3'is stretched in the extending direction of the elastic yarn 4, by In this step, extensibility is imparted to the raw material sheets 2'and 3'that do not originally have extensibility. The object to be processed in the stretchability imparting step is a composite sheet 1'obtained by fusing the elastic yarn 4 to the raw material sheets 2'and 3'through the fusion step shown in FIG. 4.

The stretchability imparting step shown in FIG. 7 is formed by alternately forming the The extension device of one of the teeth and the tooth bottom to the grooved rollers 17, 17 introduces the composite sheet 1'between the two rollers 17, 17 and conveys the composite sheet 1', whereby the composite sheet 1'runs along the The conveying direction, that is, the extending direction of the elastic yarn 4 extends, and becomes the target stretch sheet 1. The stretching device is formed with a pair of nip rollers 16, 16 arranged on the upstream side of the conveying direction of the composite sheet 1'with respect to the toothed roller 17, and a pair of nip rollers 16, 16 arranged on the downstream side of the conveying direction with respect to the toothed roller 17 A pair of nip rollers 18, 18 are used as a mechanism for the composite sheet 1'to pass between the toothed rollers 17, 17, and the composite sheet 1 can be adjusted by appropriately adjusting the conveying speed of the composite sheet 1'by using the two rollers 16, 18 'The extent of extension.

The extension device is formed with a well-known lifting mechanism (not shown) for vertically displacing one or both of the pair of toothed rollers 17, 17 and the gap between the two rollers 17, 17 can be adjusted. For example, a pair of toothed rollers 17 and 17 are combined in such a way that the teeth of one are inserted between the teeth of the other with a gap, and the teeth of the other are inserted between the teeth of the other with a gap, and the composite The sheet 1'is inserted between the two cogged rollers 17, 17 in this state, and stretchability imparting treatment is performed. Both of the pair of toothed rollers 17 and 17 may be driven by a driving source (a co-rotating roller), or only one may be driven by a driving source (a follow-up roller). As the tooth profile of the toothed roller 17, a common involute tooth profile or a cycloid tooth profile can be used, and it is particularly preferred to have a thinner tooth profile. Regarding the aforementioned flexibility expression processing, the flexibility expression processing described in Patent Document 1 can be appropriately used.

Through the above-mentioned stretchability imparting step, the thickness of the stretch sheet 1 relative to the thickness of the composite sheet 1'before the stretchability imparting step is preferably increased to 1.1 times or more, particularly preferably to 1.3 times or more, and more preferably To increase to 4 times or less, it is particularly preferable to increase to 3 times or less. Specifically, it is preferably to increase to 1.1 times or more and 4 times or less, and more preferably to 1.3 times or more and 3 times or less. Thereby, the constituent fibers of the two sheets 2 and 3 are plastically deformed and extended, whereby the fibers become thinner. At the same time, the two sheets 2, 3 becomes more fluffy, the skin feels better, and the cushioning becomes better.

Above, the present invention has been described based on one of its preferred embodiments, but the present invention is not limited to this embodiment. For example, the arrangement of the spinning nozzles in the spinning head of the present invention is not limited to the above-mentioned embodiment, and can be appropriately changed within the scope not departing from the gist of the present invention. For example, the number of nozzle rows 12L constituting the zigzag arrangement portion 12A is not particularly limited, and can be set to 3 or more in addition to 2 rows as shown in FIG. 5. In addition, the planar shape of the spinning nozzle 12 and the like may be appropriately adjusted according to the use of the stretch sheet as the manufacturing target, and there is no particular limitation.

The stretch sheet for absorbent articles manufactured by implementing the manufacturing method of the present invention is preferably used, for example, as an outer wrapper for shorts-type disposable diapers. Moreover, it is not limited to this use, and it is preferably used as a constituent material of absorbent articles such as menstrual sanitary napkins and disposable diapers. As the constituent material of the absorbent article, for example, a liquid-permeable sheet (including a surface sheet, sub-layer, etc.) located on the skin side of the absorbent body, or a sheet constituting the outer surface of a disposable diaper, is used for contrasting Waist circumference, waist, leg circumference, etc. to impart elastic stretchability, etc. Also, it can be used as a sheet forming the wings of a sanitary napkin. Moreover, even if it is a part other than this, it can also be used for the part to which stretchability is desired. When the stretch sheet for absorbent articles manufactured by the implementation of the manufacturing method of the present invention is used as the constituent material of the absorbent article, it is necessary to join with other constituent materials (for example, an absorbent body) after the stretchability imparting step The step of assembling the stretch sheet to the absorbent article is sufficient.

In this manual, when a numerical upper limit, lower limit, or upper limit is specified, the upper limit and the lower limit itself are also included. Also, even if not specifically stated, it is interpreted as All numerical values or numerical ranges within the upper limit value or lower limit value are recorded.

It is understood that various modifications or changes of the present invention can be realized by referring to the above disclosure in this specification. Therefore, it should be understood that the present invention can also be implemented for embodiments that are not explicitly described in this specification within the technical scope based on the description of the claimed scope.

The contents of the aforementioned patent documents are all incorporated into this specification as part of the content of this specification.

This case is an application claiming priority based on the Japanese patent application 2018-147827 filed on August 6, 2018, and the contents of the Japanese patent application 2018-147827 are all incorporated into this specification as a part of this specification.

In addition, the present invention further discloses the following stretch sheet and its manufacturing method.

<1>

A stretch sheet for absorbent articles, wherein a plurality of elastic filaments arranged in a manner extending in one direction without crossing each other are joined to a stretchable sheet material in a substantially non-stretched state over its entire length, and a plurality of One part or all of the above-mentioned elastic yarn is an inward yarn having one or more indented parts in a cross section orthogonal to the longitudinal direction.

<2>

The stretch sheet for absorbent articles as in the above item <1>, wherein the shape of the cross section of the inner shrinkage yarn perpendicular to the longitudinal direction has a shape in which a plurality of circles are connected in a partially repeated state, and the distance between the centers of adjacent circles It is shorter than the sum of the radius of one circle and the radius of the other circle, and is longer than the radius of the shorter one of the radius of the one circle and the radius of the other circle.

<3>

The stretch sheet for absorbent articles according to the above-mentioned <1> or the above-mentioned <2>, wherein the ratio of the number of inwardly shrinking filaments to the number of elastic filaments is 5% to 90%.

<4>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <3>, wherein the ratio of the number of shrinkable filaments to the number of elastic filaments is 5% or more and 90% or less, preferably It is 20% or more and 80% or less, more preferably 50% or more and 70% or less.

<5>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <4>, wherein the ratio of the number of the inner shrinkable filaments to the number of the elastic filaments is 50% or more and 70% or less.

<6>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <5>, which comprises a plurality of the above-mentioned shrinkage yarns, and the number of the inner shrinkage yarns having one shrinkage part is relative to the above-mentioned shrinkage The ratio of the number of threads is more than 50%.

<7>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <6>, which includes a plurality of the above-mentioned shrinkable yarns, and the number of the inner shrinkable yarns having one shrinking portion is relative to the above-mentioned shrinking The ratio of the number of threads is 50% to 100%, preferably 60% to 100%, and more preferably 90% to 100%.

<8>

The stretch sheet for absorbent articles as in any one of the above <1> to the above <7>, which contains plural The ratio of the number of inward filaments with one inward shrinkage portion to the number of inward filaments is 90% to 100%.

<9>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <8>, wherein the average value of the distance between the ends of the adjacent elastic yarns is 0.3 mm or more and 2 mm or less.

<10>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <9>, wherein the average value of the distance between the ends of the adjacent elastic yarns is 0.4mm or more and 1.2mm or less, preferably 0.6 mm or more and 1mm or less, more preferably 0.6mm or 0.8mm or less.

<11>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <10>, wherein the average value of the distance between the ends of the adjacent elastic yarns is 0.6 mm or more and 0.8 mm or less.

<12>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <11>, wherein in the cross section orthogonal to the longitudinal direction of the internal shrinkage yarn, the maximum length of the internal shrinkage yarn is 100 μm or more and 800 μm or less .

<13>

The stretch sheet for an absorbent article according to any one of the above <1> to the above <12>, wherein in the cross section orthogonal to the longitudinal direction of the internal shrinkable yarn, the maximum length of the internal shrinkable yarn is 100 μm or more and 800 μm or less It is preferably 100 μm or more and 400 μm or less, more preferably 200 μm or more and 500 μm or less, and still more preferably 200 μm or less and 270 μm or less.

<14>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <13>, wherein in the cross section orthogonal to the longitudinal direction of the internal shrinkable yarn, the maximum length of the internal shrinkable yarn is 200 μm or more and 270 μm or less .

<15>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <14>, wherein the elastic yarn joined to the sheet in a substantially non-stretched state is in a state that does not shrink when the external force is released. The entire length of the same is joined to the stretchable sheet.

<16>

The stretch sheet for absorbent articles as described in any one of the above <1> to the above <15>, wherein when an indented yarn having one indented portion is observed, a cross section orthogonal to the longitudinal direction of the indented yarn is observed , There is a pair of parts recessed from the circumferential surface of the silk toward the inner side of the cross section.

<17>

The stretch sheet for absorbent articles according to any one of the above <1> to <16>, wherein the thickness of the stretch sheet for absorbent articles is 0.32 mm or more and 0.5 mm or less, preferably 0.36 mm or more and 0.5 mm or less, More preferably, it is 0.39 mm or more and 0.4 mm or less.

<18>

The stretch sheet for absorbent articles according to any one of <1> to <17> above, wherein the thickness of the stretch sheet for absorbent articles is 0.39 mm or more and 0.4 mm or less.

<19>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <18>, wherein the peel strength of the stretch sheet for absorbent articles is 5 cN/bar or more and 30 cN/bar or less, preferably 10 cN/bar or more 20 cN/line or less, more preferably 10 cN/line or more and 18 cN/line or less. .

<20>

The stretch sheet for an absorbent article according to any one of the above <1> to the above <19>, wherein the peel strength of the stretch sheet for the absorbent article is 10 cN/piece or more and 18 cN/piece or less.

<21>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <20>, wherein the stretch sheet for the absorbent article stretches 100% along the extension direction of the elastic yarn and recovers 50% from the state The ratio of the load to the load at 50% extension along the extension direction of the elastic yarn is 45% or more and 100% or less, preferably 50% or more and 100% or less.

<22>

The stretch sheet for absorbent articles according to any one of <1> to <21> above, wherein the stretch sheet for absorbent articles stretches 100% along the extension direction of the elastic yarn and recovers 50% from this state The ratio of the load to the load at 50% extension along the extension direction of the elastic yarn is 50% or more and 100% or less.

<23>

The stretch sheet for absorbent articles according to any one of <1> to <22> above, wherein the stretch sheet for absorbent articles stretches 100% along the extension direction of the elastic yarn and recovers 50% from this state The load is 80cN/50mm or more and 150cN/50mm or less, preferably 120cN/50mm or more and 135cN/50mm or less.

<24>

The stretch sheet for absorbent articles according to any one of <1> to <23> above, wherein the stretch sheet for absorbent articles stretches 100% along the extension direction of the elastic yarn and recovers 50% from this state The load is above 120cN/50mm and below 135cN/50mm.

<25>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <24>, wherein the stretch sheet for the absorbent article has a load of 80cN/50mm or more when it stretches 50% along the extension direction of the elastic yarn 600cN/50mm or less, preferably 120cN/50mm or more and 300cN/50mm or less, more preferably 245cN/50mm or more and 250cN/50mm or less.

<26>

The stretch sheet for an absorbent article according to any one of the above <1> to the above <25>, wherein the stretch sheet for the absorbent article has a load of 245cN/50mm or more when it stretches 50% along the extension direction of the elastic yarn Below 250cN/50mm.

<27>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <26>, wherein the number of elastic yarns is directly incorporated into the stretch sheet for absorbent articles in the state immediately after spinning. The above-mentioned indented yarn with one indented portion and the above-mentioned indented yarn with two indented portions are each counted as one.

<28>

The stretch sheet for absorbent articles according to any one of the above-mentioned <1> to the above-mentioned <27>, wherein the indented portion extends in the longitudinal direction of the elastic yarn.

<29>

The stretch sheet for absorbent articles according to any one of the above <1> to the above <28>, wherein a plurality of the elastic yarns are fused to the stretchable sheet material in a substantially non-stretched state over its entire length.

<30>

An absorbent article having the stretch sheet for an absorbent article according to any one of the above <1> to the above <29>.

<31>

A shorts-type disposable diaper which uses the stretch sheet for absorbent articles as described in any one of the above <1> to the above <29> as an outer covering material.

<32>

A method for manufacturing a stretch sheet for absorbent articles, which has a fusion step that makes a plurality of elastic filaments in a molten or softened state spun from a plurality of spinning nozzles and the raw material of the sheet before the elastic filaments solidify The sheet is brought into contact with and fused with the raw sheet. In the above fusion step, a spinning head and a winding mechanism are used. The spinning head is arranged in the first direction at intervals with a plurality of nozzles of the spinning nozzles. The second direction orthogonal to the first direction forms a plurality of rows, and among the nozzle rows adjacent to each other in the second direction, the positions of the spinning nozzles are staggered in the first direction, and the winding mechanism The elastic yarn spun from the spinning nozzle of the spinning head is wound, and the elastic yarn in the molten or soft state spun from the spinning nozzle is wound at a winding speed of 40m/min or more and 200m/min or less.

<33>

The manufacturing method of the stretch sheet for absorbent articles as in the above <32>, wherein in the above fusion step, the above-mentioned elastic yarn in a molten or softened state is ejected from the above-mentioned spinning nozzle at a resin ejection speed of 5m/min or more and 30m/min or less Spun out.

<34>

The manufacturing method of the stretch sheet for absorbent articles according to the above <32> or the above <33>, wherein the winding speed is 75m/min or more and 150m/min or less.

<35>

The manufacturer of the stretch sheet for absorbent articles as in any one of the above <32> to the above <34> Method, wherein in the nozzle rows adjacent in the second direction, the distance between the centers of any nozzle in one nozzle row and the nozzle closest to the any nozzle in the other nozzle row in the first direction is Below 1mm.

<36>

The manufacturing method of a stretch sheet for absorbent articles as described in any one of the above <32> to the above <35>, which includes a stretchability imparting step by fusing a plurality of the elastic filaments to the raw material The composite sheet obtained from the sheet is provided with a pair of tooth groove rollers alternately formed with teeth and tooth bottoms in the circumferential direction, thereby imparting stretchability to the composite sheet.

<37>

A method for manufacturing an absorbent article, which has a step of assembling the stretch sheet for an absorbent article according to any one of the above <1> to the above <29> to the absorbent article.

<38>

A manufacturing method of an absorbent article, which has a step of joining the stretch sheet for an absorbent article manufactured by the manufacturing method of any one of the above-mentioned <32> to the above-mentioned <36> and other constituent materials.

[Example]

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited in any way by the examples.

[Example 1]

Using a device with the same structure as the spinning device shown in Figs. 4 to 6 and a device with the same structure as the stretching device shown in Fig. 7 to produce the same structure as the stretch sheet shown in Figs. 1 to 2 A plurality of elastic filaments include stretch sheets with shrinkable filaments. Specifically, a spinning device equipped with a spinning head in which all spinning nozzles are arranged in a zigzag pattern like the above-mentioned spinning head 11 is used to obtain a composite sheet, and the composite sheet is passed through a pair of toothed rollers as shown in FIG. 17 and 17 are generally formed alternately in the circumferential direction with one of the teeth and the bottom of the tooth and the extension device of the tooth groove roller, thereby imparting stretchability to the composite sheet, so that the elastic yarn contains the yarn with one indentation. The stretch film. The distance between spinning nozzles, resin ejection speed, and winding speed in the used device are shown in Table 1 below, and the composition of the elastic yarn of the fabricated stretch sheet with one indented portion is shown in Table 1 below. In addition, the materials used are as follows.

‧Elastic yarn: styrene-based thermoplastic elastomer

‧Sheet: Hot-air non-woven fabric with a basis weight of 20g/m ² including composite fiber (non-elastic fiber, fiber thickness 3.3dtex) containing PET in the core and PE in the sheath

‧Basis weight of stretch film: 56g/m ²

[Examples 2~4]

Except for changing the resin ejection speed and the winding speed, a stretch sheet was produced in the same manner as in Example 1.

[Comparative Example 1]

Except for changing the resin ejection speed and the winding speed, a stretch sheet was produced in the same manner as in Example 1.

[Comparative Example 2]

Except for using a spinning head in which all the spinning nozzles are arranged in a line in a straight line, a stretch sheet was produced in the same manner as in Example 1.

[Comparative Example 3]

In addition to changing the resin ejection speed, and using all spinning nozzles to be arranged in a straight line with a pitch of 1mm Except for the spinning head of one row, the stretch sheet was manufactured in the same manner as in Example 1.

[Evaluation Test]

For the stretch sheets manufactured in Examples 1 to 4 and the stretch sheets manufactured in Comparative Examples 1 to 3, sandwiched between the plates with a load of 0.5 cN/cm ² , using the laser thickness manufactured by Keyence Corporation The meter measures the distance between the plates, thereby measuring the thickness of the stretch sheet. In addition, after clamping each sheet of the stretch sheet, the sheet was peeled off at a speed of 300 mm/min, and the maximum load at that time was measured using a tensile tester manufactured by Shimadzu Corporation to measure the peeling of the stretch sheet strength. Furthermore, the above-mentioned method was used to measure the stretching force of the stretch sheet in the 100% extension cycle test, thereby measuring the 50% recovery load and 50% progress load of the stretch sheet. Then, the appearance was evaluated visually based on the following evaluation criteria. The above results are shown in Table 1.

The evaluation of the appearance of the stretch sheet is carried out by visually observing the stretch sheet of the evaluation target. The case where there is no hole etc. is set to A, the case where the hole is slightly visible is set to B, and the hole etc. is observed. The situation is set to C.

Regarding the ratio of the number of shrinkage yarns to the number of elastic yarns, the cross section obtained by cutting the stretch sheet in the width direction using a microscope manufactured by Keyence Corporation was used to observe 100 elastic yarns in the cross-sectional direction , And count the number of filaments with internal shrinkage, and calculate it as the number of internal shrinkage. Count the number of inner shrinkage filaments with 1 inner shrinkage in the inner shrinkage yarn, set it as the number of filaments with 1 inner shrinkage portion, and calculate the number of filaments with 1 inner shrinkage portion Relative to the ratio of the number of shrinkable filaments. The distance between the ends of adjacent elastic yarns is a cross-section obtained by magnifying the stretch sheet in the width direction using a microscope manufactured by Keyence Corporation, and measuring the distance between the ends at any 100 locations. Let the average value be the distance between the ends.

As shown in Table 1, the stretch sheets of Examples 1 to 4 include internal shrinkage filaments, and the 50% recovery load is equal to or higher than that of the stretch sheet of Comparative Example 1, but compared to the stretch sheet of Comparative Example 1, adjacent ones The distance (spacing) between the ends of the elastic yarns becomes wider and the thickness becomes thicker. In addition, the 50% recovery load of the stretch sheet of Examples 1 to 4 is equal to or higher than that of the stretch sheet of Comparative Example 2, but compared to the stretch sheet of Comparative Example 2, the appearance is maintained well. The stretch sheets of Examples 1 to 4 have the same appearance as the stretch sheets of Comparative Example 3, but the 50% recovery load is much larger.

Thus, according to the stretch sheet of the present invention, it can be seen that by including the inner shrinkable yarn, the touch and appearance of the skin can be maintained well, and the stress can be improved.

In addition, it can be seen from the manufacturing conditions used in Examples 1 to 4 that the spinning nozzle is equipped with The spinning head is set in a zigzag shape, and the winding speed, or the resin ejection speed and the winding speed are set to a specific speed range, which can efficiently produce shrinkage yarns with excellent skin touch, appearance and 50% recovery load The stretch film.

[Industrial availability]

According to the stretch sheet of the present invention, it is possible to provide a stretch sheet that can improve stress while maintaining good skin touch and appearance. Moreover, according to the method for manufacturing a stretch sheet of the present invention, a method for manufacturing a stretch sheet capable of efficiently manufacturing the stretch sheet can be provided.

1‧‧‧Stretching film

2‧‧‧Sheet

3‧‧‧Sheet

4‧‧‧Elastic yarn

40‧‧‧Inner shrink wire

41‧‧‧monofilament

42‧‧‧Si

43‧‧‧silk

X‧‧‧Width direction

Y‧‧‧Length direction

Z‧‧‧Thickness direction

Claims (15)

A stretch sheet for absorbent articles, wherein a plurality of elastic filaments arranged in a manner extending in one direction without crossing each other are joined to a stretchable sheet material in a substantially non-stretched state over its entire length, and a plurality of One part or all of the above-mentioned elastic yarn is an inward yarn having more than one indentation in a cross section orthogonal to the extension direction of the elastic yarn, and the above-mentioned inwardly contracted part is observed when observing the above-mentioned inward yarn In the cross section, there are parts recessed from the circumferential surface of the above-mentioned inner shrinkage wire toward the inner side of the above-mentioned cross-section. The full length in the length direction. The stretch sheet for absorbent articles according to claim 1, wherein the shape of the cross section of the inner shrinkage yarn orthogonal to the extending direction has a shape in which a plurality of circles are connected in a partially repeated state, and the distance between the centers of adjacent circles is relatively The sum of the radius of one circle and the radius of the other circle is shorter and longer than the radius of the shorter of the radius of the one circle and the radius of the other circle. The stretch sheet for absorbent articles according to claim 1, wherein the ratio of the number of shrinkable filaments to the number of elastic filaments is 5% to 90%. For example, the stretch sheet for absorbent articles of claim 1, which includes a plurality of the above-mentioned inner shrinkage yarns, and the ratio of the number of inner shrinkage yarns with one inner shrinkage portion to the number of the above-mentioned inner shrinkage yarns is 50% or more . The stretch sheet for absorbent articles of claim 1, wherein the average value of the distance between the ends of the elastic yarns adjacent to each other in the width direction is 0.3 mm or more and 2 mm or less. The stretch sheet for an absorbent article according to claim 1, wherein in the cross section of the inner shrinkable yarn orthogonal to the extending direction, the maximum length of the inner shrinkable yarn is 100 μm or more and 800 μm or less. The stretch sheet for absorbent articles according to claim 1, wherein the elastic yarn joined to the sheet in a substantially non-stretched state is joined to the stretchable sheet over its entire length in a state that does not contract when the external force is released . The stretch sheet for absorbent articles according to claim 1, wherein in a shrinkable yarn having one indentation part, when observing a cross section orthogonal to the extending direction of the inward shrinking yarn, there is a pair of circumferences from the yarn Face the recessed part of the cross section. The stretch sheet for absorbent articles according to claim 1, wherein the peel strength of the stretch sheet for absorbent articles is 5 cN/piece or more and 30 cN/piece or less. The stretch sheet for an absorbent article of claim 1, wherein the stretch sheet for the absorbent article stretches 100% along the extension direction of the elastic yarn and recovers 50% from the state and the load and the stretch along the elastic yarn The ratio of the load when the direction is extended by 50% is 45% to 100%. The stretch sheet for absorbent articles according to claim 1, wherein the indented portion extends in the extending direction of the elastic yarn. The stretch sheet for absorbent articles of claim 1, wherein a plurality of the elastic filaments and the sheet are joined by fusion. An absorbent article having the stretch sheet for absorbent articles according to any one of claims 1 to 12. A shorts type disposable diaper which uses the stretch sheet for absorbent articles according to any one of claims 1 to 12 as an outer covering material. A method for manufacturing an absorbent article, which has a step of assembling the stretch sheet for an absorbent article according to any one of claims 1 to 12 to the absorbent article.

Images